Sound familiar? Parents of tweens and teens often shrug off such anxious and gloomy thinking as normal irritability and moodiness — because it is. Still, the beginning of a new school year, with all of the required adjustments, is a good time to consider just how closely the habit of negative, exaggerated "self-talk" can affect academic and social success, self-esteem and happiness.

Psychological research shows that what we think can have a powerful influence on how we feel emotionally and physically, and on how we behave. Research also shows that our harmful thinking patterns can be changed.

You may not be of much help when it comes to sharpening your son's calculus skills. But during my 35-plus years of clinical practice it's become clear to me that parents can play a huge role in helping their children to develop a critical life skill: the ability to take notice of their thoughts, to step back and view the bigger picture, and to decide how to act based on that more realistic perspective.

Taking heed of an alarmist or pessimistic inner voice is a universal experience. It has survival value; it often protects people from danger. And it's often true that a worrying thought can act as a motivating force – to study, for example.

Still, the insecurities that adolescents feel as they undergo the multiple transitions necessary in growing up make them especially vulnerable to believing the worst. This tendency can lead to chronic anxiety, depression and anger, and can interfere with relationships and success in school.

Helping children grasp the importance of thinking more realistically may help protect them later when they make the huge transition to college. A 2016 survey by the American College Health Association of undergraduates at over 50 colleges and universities found that about 38 percent had felt so depressed at some time during the previous year that it was tough to function. Some 60 percent had experienced an episode of debilitating anxiety.

The power of thoughts to affect feelings and behavior is a foundational principle of cognitive behavioral therapy, which is the form of therapy that I practice. CBT teaches people how to recognize faulty negative self-talk, to notice how it makes them feel and act, and to challenge it. Parents can practice this skill themselves, and act as models as they guide their kids to question a thought by looking at the evidence for and against it.

If your child often seems withdrawn, sad or angry, you may be able to identify a problematic thinking pattern by listening closely. Here are four key styles of negative self-talk to listen for:

Catastrophizing. One common thought habit is the tendency to jump to the worst-case scenario ("What if I fail the test? I'm never going to get into college!") Scanning constantly for disaster ahead acts as a huge contributor to anxiety. And catastrophizing often leads teens to avoid people or become reluctant to try new things.

Zooming in on the negative. Ruminating on a disappointment without taking into account the many positive and neutral aspects of one's experience is often associated with sadness and depression. A missed soccer goal might overshadow everything else that happens one day – the lunch with friends, the good grade on a test, the hilarious TV show – and consume your high-schooler for days.

It's not fair! Interpreting every letdown as a grave injustice – the "it's not fair!" habit – often underlies teens' anger and can harm friendships and family relationships.

I can't! Reacting habitually to difficult situations or to new opportunities with "I can't," rather than "I can try," leads to helplessness. Changing the thought to "I can try!" encourages problem-solving and a willingness to be proactive, to take positive action — both keys to being successful and resilient.

For parents, the idea is not to squelch the negative thought. Research has found that attempted "thought stopping" can actually make the idea stickier. Rather, you want your child to face the thought, thoroughly examine it and replace it with a more realistic and helpful perspective.

Questions that you might pose to carefully weigh the evidence include: "You had a group of friends at your old school and at camp – realistically, what are the chances you can't make friends now? What actions can you take to reach out? What would you say to somebody else who worries about this?"

A helpful replacement thought might be: "It probably will take a few weeks to get to know people, but I've made friends before and there are things I can try. I can sign up for the photography or robotics club and meet people that way."

More realistic and balanced thinking leads to positive action, which, in turn, tends to bolster confidence, enhance self-esteem and result in greater happiness.

Mary K. Alvord, Ph.D., is a psychologist and director of Alvord, Baker & Associates, LLC, in Rockville, Md. She is the co-author of Conquer Negative Thinking for Teens: A Workbook to Break the Nine Thought Habits That Are Holding You Back, as well as the audio recording Relaxation and Self-Regulation Techniques for Children and Teens.